The Serpentine Leafminer of Aspen trees

photos taken from the Rails to Trails where a number of trees are showing infestation

photos Jenny Humphrey

The common aspen leaf miner or aspen serpentine leafminer (Phyllocnistis populiella) is a moth. The larvae  feed on the tissue between the leaf's top and bottom surface.It is found in northern North America, including Alberta, Massachusetts, Ontario and Alaska.

There seem to be number of trees affected in the area this year.
For full information:

http://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5347213.pdf